Real guilty parties here aren't two fed up passengers.

Like paying taxes or getting a colonoscopy, flying in coach can be one of modern life's unpleasant but necessary experiences. One of the ways airlines make it even less pleasant is by pitting passengers against each other for the little space left inside planes for your knees and your luggage.

So the low-grade warfare that erupted Sunday on a United Airlines flight from Newark to Denver was probably inevitable: A passenger using his laptop in Row 12 deployed small plastic clips called "Knee Defenders" to stop the passenger in front of him in Row 11 from reclining her seat and scrunching the space for his computer.

Row 11 objected, demanding to recline her seat during the four-hour flight. A flight attendant came along and told Row 12 to remove the clips, which United and all other major U.S. carriers ban. Row 12 refused. Row 11 then got up, turned around and threw a cup of water in Row 12's face.

That was enough for the pilot, who diverted the plane to Chicago O'Hare, where both combatants were barred from continuing the flight, which went on to Denver without them. Neither was arrested because Transportation Security Administration viewed this as a "customer service" issue, not a criminal matter.

Whose side you take in this might depend on how tall you are. If you're over 6 feet, you've probably had your knees banged or your useful tray space eliminated by someone who reclines the seat the maximum distance without asking. But passengers of all sizes tend to believe that their tickets — especially on long flights — come with the right to recline. Coach seats can be miserably confining, and reclining helps ease the discomfort.

Airlines now offer ways to pay your way out of pain, and, interestingly, both passengers were sitting in United's so-called Economy Plus section, where you can buy an extra 4 inches of legroom. Some passengers find this spacious. Taller ones might feel as if they're simply back in an earlier era when legroom was barely sufficient.

Whatever, both Row 12 and Row 11 need to get a grip, which their unscheduled stop in Chicago surely gave them the chance to do. If a flight attendant tells you to stop using a banned device, just do it. And throwing water in another passenger's face — just stupid.

That said, the real guilty parties here aren't two fed up passengers, but United and other major carriers that put the squeeze on passengers and carry-on bags and then leave harried flight attendants to sort out the inevitable conflicts.

USA TODAY's editorial opinions are decided by its Editorial Board, separate from the news staff. Most editorials are coupled with an opposing view — a unique USA TODAY feature.